The hot carrier relaxation dynamics in the presence and absence of a Corrole molecule are investigated. The steady-state and time-resolved photoluminescence and transient absorption spectroscopy data revealed efficient hot-hole transfer from the perovskite to Corrole.

Understanding the hot-carrier (HC) relaxation and interfacial transfer dynamics in lead halide perovskites is crucial for developing high-performance optoelectronic devices. Herein, we investigate the hot-hole relaxation and transfer from cesium lead bromide (CPB) to the corrole derivative (m-Cor) using femtosecond transient absorption spectroscopy (fs-TAS). Under above bandgap photoexcitation, the CPB/m-Cor heterostructure exhibits faster HC relaxation (∼270 fs), accompanied by narrowing of the high-energy bleach tail and reduced initial HC temperature compared to pristine CPB. These spectral signatures indicate efficient interfacial extraction of hot holes from CPB to m-Cor, which is supported by density functional theory (DFT) calculations. Furthermore, the perovskite photodetector incorporating m-Cor as the hole-transport layer (HTL) exhibits ∼56%, ∼57%, and ∼180% enhancement in photocurrent, detectivity, and responsivity, respectively. Our findings provide mechanistic insight into the interfacial hot-hole transfer in perovskite nanocrystals as well as highlight m-Cor as a promising hole-transport material for the development of efficient perovskite optoelectronics.

Ferrocene is a versatile organic compound in organic electronics and biomedical applications owing to its oxidation stability and quick response to voltage. Nevertheless, ferrocene-appended organic compounds are seldom reported because of the incompatibility of design with redox materials, regioselectivity, intricate synthetic approaches, and poor yields. Hence, we have developed a corrole-linked ferrocene derivative (Cor-Fc-Cor) and studied its self-assembled nanostructures under stimuli. Differential pulse voltammetry and UV-visible absorption spectra reveal that Cor-Fc-Cor exhibits significant changes in oxidation and reduction potentials when applying the voltage of 0.7 V and 1.2 V, which reflects on variation in Soret and Q-bands when compared to neutral molecules. Subsequently, neutral and stimulated molecules exhibit H-type aggregates through the methanol vapour diffusion approach, and their microscopic data suggest that neutral molecules show a nanosphere, which transforms to the flake-type structures at stimuli of 0.7 V and 1.2 V. Interestingly, electrochemical impedance analyses demonstrate that the self-assembled nanostructures of neutral and stimulated Cor-Fc-Cor exhibit a semiconducting nature. Therefore, this work proposes that novel synthesis and well-defined nanostructures of low-bandgap ferrocene-appended corroles serve as potential candidates for future electronics and energy device applications.

Panchromatic azaborondipyrromethenes, 1, 2, and 3, containing phenoxazine (PHO) and naphthalene tethered at 1,7 and/or 3,5-positions of the azaBODIPY platform were synthesized and photo-induced energy (PEnT) and electron transfer (PET) events were investigated. Optical absorption spectra have displayed broad absorption, from 250 to 1000 nm, in 1 and 2. Parallel electrochemical and computational studies revealed that PHO moiety in 1 and 2 was easier to oxidize compared to azaBODIPY suggesting that PHO moiety would behave as an electron donor and azaBODIPY as electron acceptor in PET reactions in these compounds. Steady-state fluorescence studies have revealed that, upon excitation of PHO moiety in 1 and 2, the emission of PHO and azaBODIPY moieties were quenched indicating the occurrence of PET from the singlet excited phenoxazine to the azaBODIPY. In contrast, excitation of naphthalene moiety in 3 revealed the quenched emission of naphthalene with concomitant appearance of the azaBODIPY emission suggesting the occurence of PEnT from (1)naphthalene* to the azaBODIPY. Fascinatingly, in 1, excitation of naphthalene moiety yielded quenched emissions of naphthalene and azaBODIPY moieties indicating the occurence of sequential PEnT from (1)(naphthalene)* to azaBODIPY followed by the PET from PHO to (1)(azaBODIPY)* leading to the formation of a charge-separated state (PHO)(2)(+center dot)-azaBODIPY(center dot)-(Naph)(2). Fluorescence decay studies revealed that the PEnT and PET in these compounds occur with rate constants of similar to 10(9) s(-1) - 10(10) s(-1).

A series of benzothiazole (BTZ) functionalized corrole (Cor) based donor-acceptor systems, Dyad-1, Dyad-2, and Dyad-3, with varied spacers, namely phenyl, biphenyl, and ethoxyphenyl respectively, were synthesized and the photoinduced energy transfer (PEnT) and electron transfer (PET) events were explored. Optical absorption studies have revealed negligible ground-state electronic interactions between the two chromophores. Steady-state fluorescence studies performed by selectively exciting the BTZ unit at 305 nm revealed a pronounced quenching of the BTZ emission, accompanied by the emergence of the corrole fluorescence indicating the occurrence of the PEnT from 1BTZ* to corrole. However, when the corrole moiety of dyads is excited at 410 nm, the emission is not quenched and found comparable with the emission intensity of the control compound, Ph-Cor, indicating that PEnT is the major photophysical pathway responsible for the quenching of BTZ emission. The electrochemical studies have shown that the first oxidation and reduction are results of the corrole moiety, corroborating with the computational results, implying that the occurrence of the PET is minimal in these dyads. Parallel lifetime measurements of the dyads have displayed a bi-exponential decay for the BTZ emission, but an unquenched corrole excited state, supporting the occurrence of the PEnT in these dyads.

In this work, we have intended and synthesized two innovative dyes, LG-P7 and LG-P8, that significantly improve the efficiency of dye-sensitized solar cells (DSCs) under outdoor and indoor/ambient illuminations. These dyes (LG-P7 and LG-P8) are modified versions of our previously reported LG-P5 and LG-P6 dyes, with the addition of an ethynyl bridge to extend pi-conjugation of the dye molecules, contributing to enhanced light harvesting behaviour. Using the asymmetric dual species copper (II/I) redox electrolyte ([Cu(II)(dmp)(2)Cl](+)/[Cu(I)(dmp)(2)](+)) and co-sensitization with the metal-free organic XY1b dye, both LG-P7/P8 devices delivered a PCE of similar to 35 % under 1000 lx WW CFL illumination, comparable to typically used D35 co-sensitized devices. The impact of introduction of ethynyl linkage was more pronounced for the D-D-pi-A dyes where moving from LG-P5:XY1b to LG-P7:XY1b, the PCE improved from 21.44 % to 35.14 % under 1000 lx CFL illumination. At a lower illumination intensity of 700 lx, the XY1b co-sensitized LG-P7/P8 devices even demonstrated superior performance compared to D35:XY1b (32.84 +/- 0.37 %), with PCE of 33.95 +/- 0.37 % (LG-P7:XY1b) and 33.03 +/- 0.16 % (LG-P8:XY1b). The introduction of extended pi-conjugation in the LG-P7 and LG-P8 dyes, compared to the parent triphenylimidazole-phenothiazine dyes (LG-P5 and LG-P6), contributed to enhanced light harvesting behaviour as well as improved photovoltaic performance further demonstrating the significance of systematic structural modifications in sensitizers to realize superior indoor photovoltaic performance in DSCs.

A sustainable approach embodying many green features and leading to a tricyclic thiopyrano[2,3-b]indole system through the base-mediated stitching together of ynones with indolin-2-thiones via a tandem Knoevenagel condensation, 6π-electrocyclization, and 1,5-H-shift reaction cascade has been observed and generalised. Initial optoelectronic profiling of these new entities reveals their potential as blue light emitters for organic light-emitting diodes (OLEDs).

Panchromatic dyes extending the absorption up to the near-infrared region stand out as excellent candidates for light harvesting and biological applications. One of the viable ways to construct panchromatic dyes involves the strategic selection of a molecular platform that can accommodate multiple chromophores absorbing at varied wavelength ranges. Even though azadipyrromethene (azaBODIPY) offers such a molecular skeleton, reports on broadband absorbing azaBODIPYs and related photoinduced interchromophore energy/electron transfer events intending to provide desirable functions such as electron migration and charge separation (CS) are still inadequate. In this context, multiheteroaromatic tethered azaBODIPY, (PTZ)2-AB-(TPA)2, containing phenothiazine (PTZ) and triphenylamine (TPA) integrated into azaBODIPY core has been synthesized and light-induced electron transfer events were explored. Parallely, control compounds involving azaBODIPYs with either TPA or PTZ moieties, (Ph)2-AB-(TPA)2 and (PTZ)2-AB-(Ph)2, and pristine Et-PTZ and TPA were synthesized, and the roles of the individual constituents in the photoinduced events are investigated. Optical absorption studies have revealed that the substitution of azaBODIPY skeleton with PTZ and TPA moieties at 1,7- and 3,5-positions enhanced the extended π-conjugation and resulted in broader absorption extending beyond 1000 nm. Electrochemical studies have displayed first oxidation from either TPA or PTZ, and first reduction from the azaBODIPY moieties indicating that TPA or PTZ would behave as electron donors and azaBODIPY as the electron acceptor, and computational studies have corroborated the results. Steady-state fluorescence studies in solvents of varied polarity, involving selective excitation of PTZ at 265 nm and TPA at 300 nm resulted in quenching of the PTZ or TPA emission indicating the occurrence of photoinduced electron transfer (PET) from 1PTZ* or 1TPA* to azaBODIPY. Time-correlated single photon counting studies confirmed the quenching of overall lifetimes of the azaBODIPYs indicating the presence of PET within these systems. Systematic femtosecond transient absorption studies revealed the optical signatures of TPA+• or PTZ+• displayed at 550 and 650 nm, respectively, authenticating the occurrence of PET from excited TPA or PTZ to azaBODIPY with a very short formation time of CS states (14, 61, and 7 ps for (PTZ)2-AB-(Ph)2, (Ph)2-AB-(TPA)2 and (PTZ)2-AB-(TPA)2, respectively), and a long charge recombination in the nanosecond time domain, and highlighted the versatility of azaBODIPY as an electron relay in light-induced events.

Heterostructures comprise two or more different semiconducting materials stacked either as co-assemblies or self-sorted based on their dynamics of aggregates. However, self-sorting in heterostructures is rather significant in improving the short exciton diffusion length and charge separation. Despite small organic molecules being known for their self-sorting nature, macrocyclic are hitherto unknown owing to unrestrained assemblies from extended pi-conjugated systems. Herein, two near infrared region (NIR) active molecules comprised of porphyrin appended D-pi-D (1) and A-pi-A (2) have been reported to show the self-assembled 0D and 2D nanostructures via J-aggregates. Interestingly, the mixture of 1 and 2 reveals self-sorting at the molecular level promoting nanosphere and sheet structures which further rolled over to spheres through pi-pi stacking leading to core-shell type heterostructure. Consequently, electrical conductivity is 10 times higher than the individual assemblies due to excited state electron transfer from 1 to 2 in a mixture, confirmed by femto second-transient absorption spectroscopy and electrochemical impedance spectroscopy. These results suggest that controlling the self-sorted heterostructures fosters refining the electronic properties which pave the way for designing novel NIR-absorbed molecules for organic solar cells (OSCs).

Controlling the dimensionality of nanostructures made from self-assembled macrocyclic systems is tedious because they attain thermodynamic stability through the extended π-conjugated structure. Mainly, corrole-based macrocycles are challenging as they form structures that make it difficult to grow hierarchical assemblies. Herein, three tetraphenylethylene (TPE) appended corroles (1-TPE-Cor, 2-TPE-Cor and 3-TPE-Cor) were developed by substituting one, two or three TPEs at the meso phenyl positions of corroles. Detailed investigations revealed that each TPE substituent influences the molecule's planarity, resulting in significant variations in optical, self-assembly, and electronic properties in the three derivatives. One-dimensional (1D) nanotubes were observed through π-π stacking for 1-TPE-Cor, while 2D nanosheets and nanospheres were seen for 2-TPE-Cor and 3-TPE-Cor. Consequently, the electrical conductivity of 1D nanotubes is 10 times higher than for the 2D and 0D nanostructures. Each TPE substituent on corroles affects their aggregation dynamics and electronic properties, and this study promotes novel corrole-based macrocyclic groups, apart from porphyrin and phthalocyanine, utilizing supramolecular interactions, paving the way to diversification in the field of electronics.

Donor-Acceptor (D-A) systems in which a triphenylamine has tethered at meso phenyl position of corrole (1-TPA-Cor) corrole monomer, (2-TPA-Cor) corrole dimer, and (3-TPA-Cor) corrole trimer have been designed and synthesized. All three D-A systems have been characterized by various spectroscopic techniques that include 1H NMR, 13C NMR, HR -MS, absorption, and emission (both steady-state and lifetime) spectroscopies as well as electrochemical methods. Optical and theoretical studies suggest that there will be π-π interactions between donor triphenylamine (TPA) and acceptor corrole (Cor) units and as a result both Soret and Q-bands are red-shifted with broadening of Soret band. Selective excitation of TPA in these D-A systems at 300 nm resulted in the quenching of TPA emission suggested the photo-induced electron transfer (PET) from 1TPA* to corrole. In contrast, excited at 405 nm also resulted in quenching of emission of Cor. As the number of corrole units and polarity of the solvent increased the quenching is more and suggested that PET reactions in these D-A systems. Time-resolved fluorescence studies shown the presence of PET within these systems and revealed an ultra-fast electron rate of ∼108 to 1010 s-1, follows the order 3-TPA-Cor > 2-TPA-Cor > 1-TPA-Cor and are polarity of solvent dependent.

Near-infrared absorbing azaborondipyrromethenes (azaBODIPYs), 1, 2, and 3, tethered with phenothiazine (PTZ) and/or naphthalene at 1,7 and/or 3,5 positions, were synthesized and photoinduced energy (PEnT) and electron (PET) events occurring within these compounds were systematically studied. Steady-state fluorescence studies have shown that, when the phenothiazine moiety, in 1 and 2, was selectively excited, the fluorescence of the PTZ and azaBODIPY was quenched, indicating the occurrence of PET from the singlet excited phenothiazine to the azaBODIPY. On the other hand, when the naphthalene moiety in 3 was excited, the emission of the naphthalene was observed to be quenched with the concomitant appearance of the azaBODIPY emission indicating the display of PEnT from (1)naphthalene* to the azaBODIPY. Interestingly, in the case of 1, selective excitation of naphthalene resulted in the quenching of both the naphthalene and azaBODIPY emissions, indicating the possibility of PEnT from (1)naphthalene* to azaBODIPY followed by a tandem PET from the ground state of the phenothiazine moiety to the azaBODIPY. The present work showed the synthetic scope of introducing two different chromophores onto the azaBODIPY platform to produce panchromatic dyes and systematically revealed the significance of the individual constituents, PTZ and naphthalene as electron and energy donors, and azaBODIPY as an excited state energy or electron receiver in the PET and PEnT processes.

Self-assembly of two similar porphyrin derivatives leads to long axial nanofibers but their mixture results in short nanorods comprising narcissistic self-sorted structures with transitional electrical conductivity.

This study employs femtosecond transient absorption spectroscopy to investigate the rapid dynamics of excited state carriers in three metalated porphyrin-naphthalimide (PN) molecules and one free-base molecule. The dynamics of electron...

The utilization of nonplanar molecularly engineered triphenylimidazole-phenothiazine donor-based dyes as efficient light harvesters in dye-sensitized solar cells (DSCs) was explored under both 1 sun and indoor/artificial light conditions. The two new sensitizers were designed and synthesized in the Donor-Donor-pi-Acceptor (D-D-pi-A, LG-P5) and Donor-Donor-Acceptor-pi-Acceptor (D-D-A-pi-A, LG-P6) architectures with a phenyl group as pi-spacer and 4-phenybenzo[c][1,2,5]thiadiazole as an auxiliary acceptor using carboxylic acid as the anchoring group. The dyes were further characterized extensively using diverse spectroscopic, electrochemical, and theoretical studies, which revealed that the ground state potential (HOMO) of the dyes is sufficiently positive (1.1 V), enabling their compatibility with the newly introduced dual-species copper redox system ([Cu(II)(dmp)(2)Cl](+)/[Cu(I)(dmp)(2)](+)). With a complementary absorption peak in the visible region, the potential of LG-P5 and LG-P6 dyes as effective co-sensitizers with standard XY1b was explored, and a systematic study under both one sun and low-light conditions (100, 200, 500, 700, and 1000 lx) was carried out. The LG-P6:XY1b cosensitized devices outperformed LG-P5:XY1b devices with efficiencies above 30% under all measured intensities, achieving the best PCE of 34.4% under standard 1000 lx illumination. A comprehensive interfacial charge transfer study was adopted using various perturbation techniques to explain the obtained photovoltaic results.

Indoor photovoltaics has received much attention in recent years mainly because of significances in human daily life for small scale device applications such as Internet of Things (IoT), remote sensors, actuators, and communication devices. Among various generations of photovoltaics, perovskite solar cells (PSCs) are found to be best suitable for indoor applications due to their easy to fabricate both on glass and flexible substrate, low-cost process and dispenses efficient power conversion efficiencies. PSCs have crossed the device efficiency of 25 % under AM 1.5G conditions and crossed the power conversion efficiency of 40 % under low-light/artificial light conditions. Therefore, there will be lot of attention on indoor perovskite photovoltaics (iPPV) in recent times towards many small device applications. The main focus of the review is to discuss recent developments in iPPVs for lead and lead-free perovskites, challenges, future direction and market opportunities.

The phase modulation exhibited by the coherent interaction of an intense light as it propagates through a nonlinear optical material, imparting a considerable nonlinear phase shift on another weak light field as they cross each other in the same medium, can be potentially exploited for all-optical switching applications. In this study, we implement this coherent light-matter interaction in pi-conjugated organic molecules-based phthalocyanine (Pc) derivatives, namely, one free-base and two metalated (Cu and Zn) phthalocyanine macrocyclic complexes, namely FbPc, CuPc, and ZnPc, respectively. Various nonlinear optical (NLO) parameters are estimated by employing the spatial self-phase modulation (SSPM) technique by considering the variation of the number of diffraction rings formed at a far field with different input excitation intensities for these molecules in both solution and thin films. The estimated range of values for nonlinear refractive index (n 2) and third-order nonlinear susceptibility (chi(3)) are similar to(1.46-11.13) x 10-5 cm2/W and similar to(2.53-20.3) 10-3 esu, respectively. Among all samples, CuPc exhibited the highest NLO response. Using cross-phase modulation (XPM), a combination of intense light and weak light of different wavelengths propagating through these materials, we demonstrated all-optical switching and OR-logic optical gate applications. These complex light-matter interactions show an emerging window for logic gates and all-optical switching applications.

A photosynthetic antenna-reaction center model, BBA-PFCor comprised of N,N'-bis( biphenyl-4- yl) aniline (BBA) covalently functionalized to bis(pentafluoro)corrole moiety has been prepared and the contribution of the BBA as the photoinduced energy transfer antenna was investigated. UV-visible studies have shown that integrating the electron-rich BBA chromophore into the corrole core has broadened the soret band of the corrole moiety with the absorption spanning from 300 to 700 nm. Electrochemical studies, in corroboration with the computational calculations, revealed that, BBA moiety can act as an electron reservoir and, in the excited state, it would transfer the excited energy to the corrole moiety in the dyad. Steady-state fluorescence studies have demonstrated that, upon photoexcitation of the BBA moiety of BBA-PFCor at 310nm in solvents of varied polarity, the BBA emission centered at 400 nm was observed to be quenched, with the concomitant appearance of the corrole emission from 500 to 700 nm, indicating the happening of photoinduced energy transfer (PEnT) from (1)BBA* to corrole moiety. Parallel control experiments involving the excitation of the corrole moiety at 410 nm did not result in the diminishing of the corrole emission, suggesting that the quenching of the BBA emission in BBA-PFCor is majorly due to intramolecular PEnT from (1)BBA* to corrole moiety leading to the formation of singlet excited corrole, that is, (1)BBA*-PFCor -> BBA(-1)PFCor*. The free energy changes of PEnT, Delta G(EnT), were found to be thermodynamically feasible in all the solvents used for the study. Parallel time-resolved fluorescence studies were congruent with the steady-state fluorescence results and provided further evidence for the occurrence of ultrafast PEnT from (1)BBA* -> corrole in the dyad with the rates of energy transfer (k(EnT)) of similar to 10(8) s(-1).